Controlled Feed Action Bolt face
Push Feed Action Bolt Face
Many shooters have heard of the term "controlled feed"Â� and "push feed"Â� when it comes to bolt action rifles, but far fewer shooters are aware of the difference between the two. And whether there is a big enough difference between the two to actually matter. In this article Pot-Shot looks at the characteristics of each type of action.
The principle behind a bolt action rifle is simple. The shooter loads a cartridge into the rifle magazine, either internal or detachable. Once the bolt is pulled to the rear the cartridge will be pushed up by the spring in the magazine, and once the bolt is pushed forward the cartridge will be stripped from the magazine and also be moved forward and chambered. Once the trigger is pulled, the bolt then gets pulled back and the empty cartridge case is ejected. This principle applies to both controlled feed and push feed bolt actions.
The difference between controlled feed and push feed is the manner in which the cartridge is handled by the bolt in the time between leaving the magazine and being securely seated inside the chamber.
With a controlled feed action the large claw extractor grips the cartridge rim as soon as the cartridge leaves the magazine. Thus the cartridge goes where the bolt goes.
With a push feed action the cartridge leaves the magazine when it is pushed out by the bolt but the bolt does not immediately grab hold of the cartridge rim at the back. It firmly grabs hold of the cartridge rim only once the bolt is closed. The extractor on a push feed action is much smaller than on a controlled feed action.
So why are there different bolt action types available and why does it matter?
Firstly, push feed actions are simpler and less expensive to manufacture than controlled feed actions. Does this make a push feed action less good than a controlled feed action? Herein lies the essence of the debate.
Controlled feed actions are slightly more reliable under very specific circumstances. Because the bolt securely grabs hold of the cartridge as soon as it starts to leave the magazine, it is not possible to get a double-feed in the chamber. While this is a reliability benefit, there is a flipside to this coin. With controlled feed actions it is necessary for cartridges to be fed via the magazine, not single loaded directly into the chamber, as it is difficult or impossible for the extractor to ride over the rim of a chambered cartridge. If a controlled feed action rifle has a worn extractor that doesn't securely grip the rim of the cartridge from the beginning of the bolt forward pushing motion then chambering problems can occur. This problem has been encountered a number of times on old surplus Yugoslavian M48 rifles (Mauser K98 clones) where very quick cycling exposes this problem.
With a push feed action a double-feed can indeed occur if a cartridge leaves the magazine and the bolt is not completely closed on such a cartridge. The cartridge will thus remain in the chamber should the bolt be retracted, and another cartridge fed from the magazine when the bolt is pushed forward will then be blocked by the back of the cartridge already seated in the chamber. This will naturally render the rifle unshootable until such time as the obstructions have been cleared. On the flipside single cartridges can be fed into the chamber and chambered with no problem in push feed actions.
The question is in which real-world situations the double-feed scenario with a push feed action might come about. In a stressful situation this is a potential event that can take place with a push feed action, especially if quick cycling of the action is required and the bolt isn't properly closed before being opened and cycled again.
The biggest advocates of controlled feed actions will obviously be hunters who hunt dangerous game, and they will insist on having top quality controlled feed actions on their large caliber rifles. As such a lot of the large caliber dangerous game rifles still come out in controlled feed actions which are essentially based on the classic Mauser K98 design. These include the CZ 550, Ruger's M77 and Winchester's Model 70.
What is important to bear in mind though, is that an armed enemy soldier or terrorist is equally if not more deadly than dangerous game. And the reason this is a relevant point is that the US military has been using push feed actions on their bolt action sniper rifles for decades, notably the venerable Remington Model 700. Reliability in stressful situations has clearly not been an issue for American snipers with their push feed rifles, but sufficient training and familiarity with their equipment likely plays a role.
At the end of the day, the decision to go for a controlled feed rather than a push feed action will likely be determined by personal preference rather than inherent reliability issues. As with most hunting gear, knowing your equipment and how to use it is the most important consideration in ensuring success.
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